Method of protecting cells



June 9, 1959 c. w. RAETZSCH ,8

I METHOD OF PROTECTING CELLS Filed Dec. 20, 1956 :r-LQ- e cououcroa STEEL aemromuc NETWORK INVENTOR. 61404 1 244672566 METHOD or PROTECTING CELLS Carl W. Raetzsch, Corpus Christi, Tern, assignor to Columbia-Southern Chemical Corporation, Allegheny County, Pa, a corporation of Delaware Application December 20, 1956, Serial No. 629,511

3 Claims. (Cl. 204-98) The present invention relates to an improved electrolytic cell for use in the electrolysis, for instance, of alkali metal chloride solutions to prepare chlorine and alkali metal hydroxide. More particularly, the invention concerns a method for protecting cell parts, such as concrete cell bottoms or the like, from cracking or fracturing during use.

Electrolytic chlorine cell operators and manufacturers have for years been plagued with the fact that, after a certain period of use, electrolytic cell bottoms, usually made of concrete reinforced with steel rods, fracture to the point where they are no longer serviceable and must be replaced. Needless to say, frequent replacement of concrete cell bottoms for commercial electrolytic cells is a substantial economic burden, particularly from the point of view of loss of operating time, cost of equipment and installation.

In other words, the art has long been cognizant of the problem and has learned to live with it as the necessary evil attending operation of electrolytic cells, such as chlorine cells. According to the present invention, however, a method has been discovered which prevents or substantially minimizes fracturing and disintegration of the concrete base as a result of continued use. Consequently, the

long-standing problem which constituted a necessary evil in the operation of electrolytic cells has been virtually eliminated.

It has been found, according to the present invention, that the steel-reinforced concrete bottom of an electrolytic cell (having, as well, anodes, cathodes and a top) may be protected from splitting and cracking by electrically connecting the reinforcing metal with a negative pole of an electric potential source. For example, one end of a conductor, such as a copper wire, may be attached to the metal reinforcing network inside the concrete bottom and the other end of the conductor to the cathode of the cell, whereby the metal network and the cathode are at substantially the same potential.

The present invention will be better understood by reference to the following drawing which is but a specific embodiment of the invention. It is by no means intended that the scope of the invention be limited to said embodiment, however, since numerous modifications and applications will be obvious to one skilled in the art.

Figure 1 of the drawing is a fragmentary side elevation of an electrolytic cell showing parts of the cell in crosssection. The cell is, generally, of the type described in US. Patent 1,866,065, issued July 5, 1932. It has a concrete bottom reinforced with steel rods embedded in the concrete. The concrete base supports a plurality of flat graphite slabs placed in parallel alignment in an upright position, the slabs being spaced one from the other and serving as anodes. In the spaces between the anodes are hollow, elongated cathode members which are electrically connected with the cathode plate shown in the drawing.

According to the present invention, one end of a wire, preferably a copper wire, is attached to the cathode plate (as shown) and the other end of the wire to the steel reinforcing network of the concrete bottom. This provides a low-resistance current path from the cathode to the steel. Thus, the cathode and reinforcing steel are at substantially the same potential when the cell is in operation.

By the technique shown herein, the troublesome and costly disintegration of the concrete bottoms occurring during use of the electrolytic cell has been substantially minimized. In addition, it has been found that the power required to effect this very desirous protection is very low, generally less than 0.7 ampere per cell. Quite obviously, the protection is afforded at a very low cost and the savings resulting therefrom are very substantial. Accordingly, the instant invention quite handily solves the problems which have long plagued electrolytic cell operators and manufacturers.

As stated hereinabove, although the invention is described with particular reference to specific embodiments thereof, it is by no means limited to the details of said embodiment. For example, cell parts, such as concrete bases containing metal reinforcing rods, may be protected by electrically connecting the rods with the negative pole of an electric potential source exterior to the cathodic system, such as to an external source of direct current. These and numerous other modifications which will be apparent to one skilled in the art are clearly within the contemplation of the present invention. Furthermore, it is not intended that these details impose any undue restrictions upon the appended claims.

I claim:

1. In an electrolytic cell for treating alkali metal chloride solutions to produce chlorine and alkali metal hydroxide, said cell having anodes, cathodes, a top and a concrete bottom reinforced with metal embedded therein, the improvement which comprises protecting the concrete bottom of said cell by electrically connecting the reinforcing metal to the negative pole of an electric potential source and maintaining the cathode and the reinforcing metal at substantially the same potential.

2. In an electrolytic cell for treating alkali metal chloride solutions to produce chlorine and alkali metal hydroxide, said cell having anodes, cathodes, a top and a concrete bottom reinforced with metal rods embedded therein, the improvement which comprises a conductor in electrical contact with said rods and the negative pole of an electric potential source.

3. In an electrolytic cell for treating alkali metal chloride solutions to produce chlorine and alkali metal hy droxide, said cell having anodes, cathodes, a top and a concrete bottom reinforced with metal rods embedded therein, the improvement which comprises a conductor in electrical contact with the cathode and said rods, whereby the rods and the cathode are at substantially the same potential.

References Cited in the file of this patent UNITED STATES PATENTS Re. 23,559 Andrus Sept. 30, 1952 641,438 Darling Jan. 16, 1900 1,055,327 Hering Mar. 11, 1913 1,411,530 Statham Apr. 4, 1922 1,545,384 Achcroft July 7, 1925 1,580,469 Dolter Apr. 13, 1926 2,311,257 Sawyer et al Feb. 16, 1943 2,508,523 Krebs May 23, 1950 OTHER REFERENCES Evans: Metallic Corrosion Passivity and Protector, London, Edward Arnold and Company, 1948, pages 42 and 43. 

1. IN AN ELECTROLYTIC CELL FOR TREATING ALKALI METAL CHLORIDE SOLUTIONS TO PRODUCE CHLORINE AND ALKALI METAL HYDROXIDE, SAID CELL HAVING ANODES, CATHODES, A TOP AND A CONCRETE BOTTOM REINFORCED WITH METAL EMBEDDED THEREIN, THE IMPROVEMENT WHICH COMPRISES PROTECTING THE CONCRETE BOTTOM OF SAID CELL BY ELECTRICALLY CONNECTING THE REINFORCING METAL TO THE NEGATIVE POLE OF AN ELECTRIC POTENTIAL SOURCE AND MAINTAINING THE CATHODE AND THE REINFORCING METAL AT SUBSTANTIALLY THE SAME POTENTIAL. 